Incidence of haemolytic disease of the newborn in Harare, Zimbabwe.

BACKGROUND: Haemolytic Disease of Newborn is responsible for a number of neonatal deaths and complications worldwide. Its incidence in Zimbabwe is not clearly understood. OBJECTIVE: To find out incidence of Haemolytic Disease of Newborn in Harare and ability to identify antibodies associated with HDN. METHODS: A retrospective cross sectional study at the Parirenyatwa Group of Hospitals and National Blood Service, Zimbabwe (NBSZ). We studied 22493 infants at Parirenyatwa Hospital during the 1995-1997 and 2002-2003 periods. The main outcome measures were ABO and Rh blood group results, Direct Antiglobulin Test and Maternal Antibody Screening and Identification Results were obtained from the NBSZ. RESULTS: One hundred and ninety-one (0.85%) infants had Haemolytic Disease of Newborn. One hundred and sixty-three (85.34%) of these were due to anti-AB, twenty five (13.09%) were due to anti-D and three (1.57%) due to anti-Kell. Incidence of Haemolytic Disease of Newborn during 1995-1997 and 2002-2003, were 0.93% and 0.64%, respectively (p = 0.014). ABO Haemolytic Disease of Newborn showed a statistically significant difference during the two periods (p = 0.003). Rhesus Haemolytic Disease of Newborn showed no statistically significant difference during same periods (p = 0.317). CONCLUSION: The incidence of Haemolytic Disease of Newborn at Parirenyatwa Hospital is comparable with that found in other countries. It is recommended that K antigen be included in the pretransfusion testing to avoid anti-K related Haemolytic Disease of Newborn.

Demographic and social characteristics of regular donors who sero-converted in Harare.

Zimbabwe, like any other country, is currently experiencing a fast growing HIV/AIDS pandemic. A considerable number of infections are caused by blood transfusion. The aim of this study is to determine risk factors, events and socio-demographic characteristics associated with incidence of HIV infections and to prevent sero-conversion of regular blood donor. A retrospective cross sectional study was done. 22,922 regular donors at National Blood Transfusion Services in Harare were used. The number of all regular donors who sero-converted and their status during the 1999 to 2001 period were determined. About 327 (1.4%) of the regular donors sero-converted. Two hundred and seventy-four (84%) were males and 53(16%) were females. 52.6% of the males were married, 46.7% were single and .7% separated. 30.2% of the females were married, single women 67.9% and separated women 1.9%. Increased sero-conversion was associated with unemployment, high-density area residence and the sexually active age group (21 to 45 year olds). There was an association between gender and marital status among sero-converters (c2 = 8.48; P-value = 0.014) and males were likely to be older than females (t = 2.9; P-value = 0.0019). It can be concluded that unemployment and living in high-density residential areas are highly associated with HIV sero-conversion among regular donors. Single females, working class males and the sexually active age group are highly exposed to risk factors. It is recommended that donor education schemes and knowledge of these factors should be considered during donor recruitment.

Prevalence of HIV infection in school based and other young donors during the 2002 and 2003 period.

The majority of donor blood in Zimbabwe comes from school-based donors. Zimbabwe has one of the highest HIV prevalences in the world and the age at which the infection is acquired is decreasing. This is a serious threat to the safety of blood supply. The prevalence of HIV has been low among the youth the majority of whom are still going to school and between the ages of sixteen and nineteen years. However, due to the changing socio-economic environment, sexual behavioural patterns have also changed. It is now necessary to evaluate these changes in order to guarantee safe blood transfusion. To determine the prevalence of HIV among adolescent donors during the period between 2002 and 2003. Cross-sectional retrospective study, National Blood Transfusion Service (NBTS). All school based donors and others between 16 and 19 years of age. The number of donors who were HIV positive in this age group. Data on donors was collected from computer files at the National Blood Transfusion Service (NBTS) Information Technology (IT) department. Prevalence of HIV was determined and categorised according to gender, age and the type of school the donor attended. The prevalence of HIV in 2002 and 2003 were 0.48% and 0.38%, respectively. Sixty-six per cent (66%) of HIV positive donors had donated for the first time. The prevalence in both periods was much higher in female donors than male donors. In 2002 males and females had prevalence of 0.28% and 0.66%, respectively. In 2003 males and females had prevalence of 0.18% and 0.55%, respectively. The overall highest prevalence (0.90%) was found between the 16-19 year age group who were not going to school (others). In 2002 female day schools had the highest (0.87%). The lowest prevalence (0%) was found in male boarding schools. In 2003 the highest prevalence (1.61%) was found in the 16-19 year age group who were not going to school (others). The lowest prevalence (0) in the same year was found in male boarding scholars. It can be concluded that the majority of HIV positive school based donors are first time donors. Female scholars and those of the same age group who are not going to school have the highest risk of donating HIV positive blood than male donors. The prevalence of HIV in adolescent blood donors decreased with age. It is recommended that active donor recruitment should be in favour of the low prevalence groups.

The prevalence of Herpes simplex virus type-2 infection in blood donors in Harare, Zimbabwe.

OBJECTIVE: To determine the prevalence of HSV-2 infections in a population of blood donors. DESIGN: Cross sectional study. SETTING: Harare Blood Transfusion Service (BTS) Centre. SUBJECTS: 314 serum specimens of voluntary blood donors. MAIN OUTCOME MEASURES: HSV-2 sero-prevalence. RESULTS: The median age (Q1, Q3) of the blood donors was 18 (17,27) years and 65% of them were males. HSV-2 infection was detected in 29 (9.7%) of the 299 specimens that were analyzed. There was a strong association between age of blood donors and HSV-2 seropositivity (p < 0.001). Older blood donors tended to be positive while younger donors tended to be negative for HSV-2 antibodies. Though not as strong, there was also an association between HSV-2 and HIV seropositivity (p = 0.048). CONCLUSION: The prevalence of HSV-2 infections in blood donors in Harare is high, considering the nature of the population studied. Therefore, the testing for HSV-2 in the serum of prospective blood donors should be included in the screening profiles used at the BTS centre in Harare, Zimbabwe to improve blood and blood products.

Worldwide ethnic distribution of the G protein beta3 subunit 825T allele and its association with obesity in Caucasian, Chinese, and Black African individuals.

Recently, it was demonstrated that one allele (825T) of the gene encoding the G protein beta3 subunit (GNB3) is associated with hypertension in Germans. This study investigates a possible association with obesity in young male Germans, Chinese, and black South Africans with low, intermediate, and high 825T allele frequencies, respectively. In each of these three distinct cohorts, the 825T allele frequency was increased significantly in overweight (body mass index [BMI] > or =25 kg/m2) and obese individuals (BMI >27 kg/m2) compared to those with normal weight. The 825T allele frequencies in these three BMI groups were, respectively, 29.5, 39.3, and 47.7% in Germans, 46.8, 53.9, and 58.6% in Chinese, and 83.1, 87.7, and 90.9% in South Africans. In each of these three distinct groups, the 825T allele was significantly associated with obesity with odds ratios between 2 and 3. More urban than rural black Africans were overweight despite similar 825T allele frequencies in both populations, which underscores the role of both genetic and environmental factors. BP values in young male whites increased significantly with increasing BMI values but were independent of the C825T polymorphism, suggesting that hypertension associated with the 825T allele could be a consequence of obesity. Genotyping of 5254 individuals from 55 native population samples from Africa, the Americas, Europe, Asia, Australia, and New Guinea demonstrated highest 825T allele frequencies in black Africans (82%) and intermediate values in east Asians (47%). It is anticipated that high frequencies of the 825T allele in Africans and Asians may contribute to an obesity and hypertension epidemic if Westernization of lifestyles continues.

Risk factors for HIV seropositivity among first-time blood donors in Zimbabwe.

BACKGROUND: Factors associated with an increased likelihood of HIV infection among newly recruited blood donors in Zimbabwe are identified. Their feasibility as criteria for exclusion from donation is assessed. STUDY DESIGN AND METHODS: A self-administered survey including demographic and behavioral questions was completed by 1199 first-time, volunteer blood donors in Harare, Zimbabwe. Methods for subject recruitment and laboratory screening followed usual blood bank protocols. RESULTS: Fifteen percent of subjects were HIV positive. Factors significantly associated with HIV seropositivity at the p<0.05 level included recruitment venue, age, marital status, donor residence, residence of primary partner, occupation, history of sexually transmitted disease, and condom use. An exclusion strategy based on donor age, condom use, recruitment venue, sexually transmitted disease history, and residence of primary partner would exclude a large proportion of HIV-infected donors without substantial loss of uninfected donors. CONCLUSIONS: Exclusion of donors who are likely to be infected with HIV is a sound policy for improving blood safety and reducing operating costs worldwide. Identification of efficient donor selection criteria requires knowledge of the local epidemiology of HIV infection and the asking of questions that are likely to be answered accurately.

PIP: Sub-Saharan Africa is the region of the world which is most severely affected by HIV infection and the AIDS pandemic. The region also has a disproportionately high level of transfusion-associated HIV transmission due to the high prevalence and incidence of HIV infection in the general population and the paucity of resources with which to fully implement effective prevention measures. Since 1985, Zimbabwe's National Blood Transfusion Service (NBTS) has screened all donated blood for HIV antibodies. First-time adult donors have the highest prevalence of HIV infection of all donor groups, with 10% of such donors in 1993 and 1994 being infected. New adult donors accounted for more than 50% of all HIV-positive donations even though they provided only 10% of donations overall. A self-administered survey including demographic and behavioral questions was completed by 1199 adult, first-time, volunteer blood donors in Harare, Zimbabwe, in an attempt to identify risk factors for HIV infection which could serve as feasible criteria for excluding high-risk first-time blood donors in the country. 15% of study participants were HIV-positive. The following factors were significantly associated with HIV seropositivity: recruitment venue, age, marital status, donor residence, residence of primary partner, occupation, history of STD, and condom use. An exclusion strategy based upon donor age, condom use, recruitment venue, STD history, and primary partner's residence would exclude a large proportion of HIV-infected donors without substantial loss of uninfected donors.

Risk factors for prevalent and incident HIV infection in a cohort of volunteer blood donors in Harare, Zimbabwe: implications for blood safety.

OBJECTIVES: To compare risk factors for HIV seropositivity with risk factors for HIV seroconversion in a population of volunteer blood donors in Harare, Zimbabwe, and to assess the impact of risk factor exclusion strategies on the safety of the blood supply. DESIGN: A secondary analysis of a longitudinal cohort study was performed. SUBJECTS AND METHODS: The subjects were volunteer blood donors who were also taking part in a prospective cohort study in Harare, Zimbabwe. They were tested for HIV antibodies upon enrollment and at 6-month intervals. Their donation history, age, marital status and the presence or absence of multiple sex partners and paying for sex were assessed as predictors of HIV seropositivity and HIV seroconversion. The impact of exclusion strategies on blood safety was modeled by estimating the number of HIV-infected units that would escape detection by antibody screening if blood donors with these risk factors were excluded. RESULTS: The HIV seroprevalence among persons accepted for blood donation was 8.8%; the HIV seroincidence was 2.1 per 100 person-years. Significant risk factors for HIV seropositivity were being a new donor (odds ratio 7.3, 95% confidence interval 4.4-1 2.1), age over 25 years (odds ratio 1.6, confidence interval 1.1-2.4), being married (odds ratio 1.7, confidence interval 1.2-2.6), paying for sex (odds ratio 2.6, confidence interval 1.7-3.9) and multiple sex partners (odds ratio 2.1, confidence interval 1.4-2.9). Significant risk factors for HIV seroconversion were age under 25 years (hazard ratio 2.5, confidence interval 1.4-5.0) and being unmarried (hazard ratio 2.5, confidence interval 1.4-5.0). Of note, age and marital status reversed their direction of association with respect to HIV seropositivity and HIV seroconversion. Exclusion strategies based on strong predictors of HIV seroconversion were the most effective in improving the safety of the blood supply. CONCLUSIONS: A distinction between risk factors for HIV seropositivity and HIV seroconversion is necessary in order to develop strategies to reduce the residual risk of transfusion-associated HIV transmission. Because window-period donations are the most important source of residual HIV contamination and arise from incident infections, research to develop risk factor exclusion strategies must focus on predictors of HIV seroconversion.

PIP: Secondary analysis of data from a longitudinal cohort study of voluntary blood donors in Harare, Zimbabwe, confirmed a residual risk of HIV contamination of blood due to laboratory false-negatives and donations made during the window period. It further identified different risk factors for prevalent HIV infection (HIV seropositivity) compared with incident HIV (HIV seroconversion). The HIV prevalence rate among the 1515 blood donors enrolled in the study during 1993-95 was 8.8% (2.1 per 100 person-years). HIV seroprevalence was highest among first-time donors, those 21-45 years of age, married persons, those with more than 1 sexual partner in the preceding year, and those who had paid for sex in the past year. Among the 1142 initially HIV-negative donors who had at least 1 6-month follow-up test, there were 40 seroconversions (2.1 per 100 person-years). Significant risk factors for seroconversion were age under 25 years and single marital status. Since window-period donations account for substantially more HIV contamination of the blood supply than laboratory false-negatives, donor exclusion criteria based on risk factors for incident HIV infection are more likely to reduce the residual risk of HIV contamination than exclusion criteria based on risk factors for prevalent HIV infection.

Epidemiology and prevention of transfusion-associated human immunodeficiency virus transmission in sub-Saharan Africa.

BACKGROUND AND OBJECTIVES: Compared to industrialised nations, countries in sub-Saharan Africa experience a greater amount of transfusion-associated HIV transmission due to high rates of transfusion in some groups of patients, a higher incidence and prevalence of HIV infection in donor populations, a lack of HIV antibody screening in some areas, and a higher residual risk of contamination in blood supplies despite antibody screening. MATERIALS AND METHODS: Epidemiologic review. RESULTS: Epidemiologic evidence supports the effectiveness of three relatively inexpensive strategies to prevent transfusion-associated HIV transmission in sub-Saharan Africa: HIV antibody screening, avoidance of unnecessary use of blood products, and exclusion of donors at high risk of infection. Such prevention strategies have not been universally implemented. CONCLUSIONS: International aid to establish and maintain HIV antibody screening programmes, implementation of sound criteria for transfusion, and the search for HIV risk factors to use as donor exclusion criteria must be expanded in the region.

Rapid and simple hepatitis assays: encouraging results from a blood donor population in Zimbabwe.

A rapid assay to detect antibodies to hepatitis C virus (HCV) in serum and two rapid/simple assays to detect hepatitis B surface antigen (HBsAg) in whole blood/serum were evaluated for their accuracy and suitability at the National Blood Transfusion Service, Harare, Zimbabwe. For this purpose, a total of 206 sera (196 routinely collected and 10 frozen) were tested using the HCV-SPOT (Genelabs Diagnostics), the SimpliRED HBsAg test (AGEN), and the Dipstick-HBsAg (PATH/Immuno-Chemical Laboratories). The results were compared with those obtained using a routine HBsAg enzyme immunoassay (EIA) (Auszyme, Abbott) and an HCV IgG second-generation EIA (Abbott). An HCV IgM test (Abbott) was used for samples that produced discordant results, and all HCV-reactive samples were confirmed using the INNO-LIA HCV Ab III synthetic peptide assay (Innogenetics). Overall, the concordance between the HCV-SPOT and the HCV EIA was 97.6% (201/206). For the 193 sera that were true HCV negatives, the number of false positives was six with the HCV-SPOT test, while the HCV EIA produced three (specificity = 97.0% and 98.5%, resp.). Of these false positives, two were so in both tests. None of the false positives contained IgM antibodies to HCV, and there were no false negatives in the two HCV tests. The concordance between the two rapid HBsAg tests and the HBsAg EIA was 99.5% (205/206). All the rapid/simple tests were easy to perform and interpret, required no (or minimal) laboratory equipment, and could be taught easily to local laboratory personnel. The cost of these tests is equivalent to or less than that of routine EIA methods.

Deferral of blood donors with risk factors for HIV infection saves lives and money in Zimbabwe.

We compared the cost-effectiveness of three strategies to avert transfusion-associated HIV infection in Zimbabwe: HIV antibody testing, deferral of donors with HIV risk factors, and deferral of donors with risk factors followed by antibody testing ("Defer/Test"). The Defer/Test strategy averted the most HIV infections. Compared with antibody testing alone, the Defer/Test strategy, using history of genital ulcer or any sexually transmitted disease as a criterion for deferral, resulted in net savings. The cost per HIV-infected unit averted using history of paying for sex or having had multiple sex partners was $ 127 and $ 773, respectively. We discern four benefits of risk factor-based deferral before antibody testing. First, deferring donors at risk lessens collection of blood in the window period. Second, deferring donors likely to be HIV positive minimizes the number of units discarded. Third, ascertainment of donor risk provides an opportunity for AIDS education and prevention. Fourth, the number of false negatives is lower with a lower HIV prevalence among accepted donors. The Defer/Test strategy is cost-effective in Zimbabwe because additional recruitment costs are offset by discarding fewer HIV-positive units. We predict the Defer/Test strategy will be cost-effective in other sub-Saharan African donor populations.

Characteristics of anti-A and anti-B in black Zimbabweans.

Sera from young, black, group 0 Zimbabwean blood donors were screened for anti-A and anti-B haemolysins. Nearly one fifth of the sera were found to be strongly haemolytic for either A or B cells or both. Some of the sera were titrated for agglutination in saline before and after treatment with dithiothreitol. Serum dilutions beyond the endpoint of agglutination were further tested by the indirect antiglobulin technique using specific anti-IgM and anti-IgG sera. More than 60% of the strongly lytic sera had high titres of IgG (> or = 64). The IgM and IgG concentrations both of anti-A and anti-B were correlated and these levels were in turn correlated with haemolytic activity.

Distribution of HLA-DQA1, -DQB1 and DRB1 alleles in black IDDM patients and controls from Zimbabwe.

We have used the XI Histocompatibility Workshop sequence-specific oligonucleotide probes to determine the DRB1, DQA1 and DQB1 genotypes by dot-blot hybridization of polymerase chain reaction (pcr)-amplified material from a homogenous black population in Zimbabwe. The DR4 subtype DRB1*0405, the DR3 subtype DRB1*0301, DQB1*0201 and DQB1*0302 and DQA1*0301 and DQA1*0501 were significantly increased in the IDDM group compared to the controls, whereas DRB1*11, DQB1*0602 and DQA1*0102 were significantly decreased. Taken together, the data show that susceptibility and resistance to IDDM are associated both with particular haplotypes and DQA1-DQB1 heterodimers without one or other being overriding.